Re: strange guest slowness after some time

[Tomasz Chmielewski <mangoo@wpkg.org>]

Tomasz Chmielewski schrieb:

> As I mentioned, it was using virtio net.
> 
> Guests running with e1000 (and virtio_blk) don't have this problem.

Also, virtio_console seem to be affected by this "slowness" issue.

Am I correct to think that if:

* on guest "lsmod" outputs:

     virtio_console          6828  0 [permanent]

* on guest, /etc/inittab contains:

6:2345:respawn:/sbin/mingetty ttyS0

* on host, I start the guest with a parameter:

-serial unix:/var/run/qemu-server/103.serial,server,nowait


That the guests's ttyS0 console is "virtio_console"?



If my thinking is correct, than I have a "slow serial console" on some 
of the guests using virtio_pci and virtio_console driver.


By "slow serial console" I mean any character typed shows up after a 
second or so.

It can be also "cured" like with virtio_net - just run:

     dd if=/dev/vda of=/dev/null

And the console reacts normally. Stop dd, console is slow again.


I have this issue on two guests with e1000 network, which use virtio_blk 
(and virtio_console...).
I never saw this issue with guests which don't use virtio.



-- 
Tomasz Chmielewski
http://wpkg.org